US20050196721A1 - Portable LED curing light - Google Patents

Abstract

A portable LED curing light for dental applications includes a one-piece handle assembly with an angled light-producing end for positioning within a patient's mouth for curing a dental material. A replaceable lens for focusing light emitted by an LED light source is removably attached at the light-producing end. The handle also includes a battery and associated electronics for operating the light, including an operating switch, an audible indicator and at least one visual indicator. The handle is coupled with a base for storage and recharging, which positions the handle at an inclined position for draining moisture away from the handle. Circuitry in the handle monitors the status of battery voltage and handle temperature, and prevents operation of the switch from initiating a next curing cycle when battery voltage is determined to be too low or handle temperature is determined to be too high.

Description

CROSS-REFERENCE TO RELATED APPLICATION
• The present application claims priority under 35 U.S.C.§ 119(e) from U.S. Ser. No. 60/545,656, entitled “Portable LED Curing Light,” filed on Feb. 18, 2004. U.S. Ser. No. 60/545,656 was filed by at least one inventor common to the present application, and is hereby incorporated by reference.
FIELD OF THE INVENTION
• The present invention relates to a light used for curing light-activated compound materials. In particular, the present invention relates to a portable rechargeable curing light for dental applications.
BACKGROUND OF THE INVENTION
• Light-activated compounds are well known and used in a variety of commercial applications. For example, such compounds are widely used in a variety of dental procedures including restoration work and teeth filling after root canals and other procedures requiring drilling. Several well-known dental compounds have been sold, for example, under the trade names of BRILLIANT LINE, Z-100, TPH, CHARISMA and HERCULITE & BRODIGY.
• Dental compounds typically comprise liquid and powder components mixed together to form a paste. Curing of the compound requires the liquid component to evaporate, causing the composite to harden. In the past, curing has been accomplished by air drying, which has had the disadvantage of requiring significant time. This time can greatly inconvenience the patient. More recently, use of composite materials containing light-activated accelerators has become popular in the field of dentistry as a means for decreasing curing times. According to this trend, curing lights have been developed for dental curing applications. An example of such a curing light is illustrated by U.S. Pat. No. 5,975,895, issued Nov. 2, 1999 to Sullivan.
• Conventional dental curing lights have employed tungsten filament halogen lamps that incorporate a filament for generating light, a reflector for directing light, and often a filter for limiting transmitted wavelengths. For example, a blue filter may be used to limit transmitted light to wavelengths in the region of 400 to 500 nanometers (nm). Light is typically directed from the filtered lamp to a light guide, which directs the light emanating from an application end of the guide to a position adjacent to the material to be cured.
• Filters are generally selected in accordance with the light activation properties of selected composite compound materials. For example, blue light may be found to be effective to excite composite accelerators such as camphoroquinine, which has a blue light absorption peak of approximately 470 nanometers (nm). Once excited, the camphoroquinine accelerator in turn stimulates the production of free radicals in a tertiary amine component of the composite, causing polymerization and hardening.
• A problem with conventional halogen-based lights is that the lamp, filter and reflector degrade over time. This degradation is particularly accelerated, for example, by the significant heat generated by the halogen lamp. For example, this heat may cause filters to blister and cause reflectors to discolor, leading to reductions in light output and curing effectiveness. While heat may be dissipated by adding a fan unit to the light, the fan may cause other undesired effects (for example, undesirably dispersing a bacterial aerosol that may have been applied by the dentist to the patient's mouth). Alternate lamp technologies using Xenon and other laser light sources have been investigated, but these technologies have tended to be costly, consumed large amounts of power and generated significant heat. Laser technologies have also required stringent safety precautions.
• Light Emitting Diodes (LEDs) offer a good alternative to halogen curing light sources, having excellent cost and life characteristics. Generating little heat, they also present less risk of irritation or discomfort to the patient. However, in the past, LEDs have been capable of generating only modest optical power levels. As a result, many prior art curing lights have required arrays of LEDs to generate sufficient optical power levels for curing applications (see, e.g., U.S. Pat. No. 6,331,111 to Cao).
• More recently, the electrical and optical power outputs for LEDs have improved substantially. For example, LEDs are currently capable of producing powers in excess of 1 watt at efficiencies in excess of 45 percent to generate more than 100 lumens per watt (see, e.g., Eric Learner, “Solid-state illumination is on the horizon, but challenges remain”, Laser Focus World, November 2002). Accordingly, it would be desirable to produce a compact, portable LED curing light for use in dental curing applications.
SUMMARY OF THE INVENTION
• A portable LED curing light is disclosed, with application to curing of dental materials and other related applications. The light includes a one-piece handle assembly including a slim probe portion with an angled light-producing end that is suitable, for example, to be positioned within a dental patient's mouth for curing a dental material positioned in a tooth of the patient. A replaceable lens for focusing light emitted by an LED light source is removably attached at the light-producing end. The handle also includes a battery and associated electronics for operating the light, including an operating switch, an audible indicator and at least one visual indicator. The handle is coupled with a base for storage and recharging of the battery. The base positions the handle at an inclined position, and provides a drain for draining moisture away from the handle.
• Upon operation of the switch, the light may be operated for a predetermined curing cycle, after which power is automatically removed (“sleep mode”). An audible beep is produced at predetermined intervals during the curing cycle so that a desired curing time can be determined and achieved. Circuitry in the handle monitors the status of battery voltage and handle temperature. Based on predetermined thresholds, if either battery voltage is determined to be too low or handle temperature is determined to be too high, the circuitry prevents operation of the switch from initiating a next curing cycle. If the light is currently operating in a current curing cycle at a time at which either battery voltage is determined to be too low or handle temperature is determined to be too high, the light continues to operate through completion of the duty cycle. The visual indicator indicates when either battery voltage is determined to be too low or handle temperature is determined to be too high.
BRIEF DESCRIPTION OF THE DRAWING
• A more complete understanding of the invention may be obtained by reference to the appended drawing in which:
• FIGS.1(a)-1(f) provide orthographic and perspective views of a handle of the disclosed LED curing light;
• FIG. 2 provides an exploded view of the curing light handle;
• FIGS.3(a)-3(d) provide orthographic and perspective views of a heat sink for dissipating heat in the curing light handle;
• FIGS.4(a)-4(d) provides several views of a ball lens affixed to the curing light handle for focusing light emitted by the LED;
• FIG. 5 illustrated features of a left housing case of the curing light handle;
• FIG. 6 illustrates features of a right housing case of the curing light handle;
• FIG. 7 presents a schematic diagram of a circuit for operating the curing light handle;
• FIG. 8 presents a schematic diagram of a circuit for charging a battery in the base;
• FIGS.9(a),9(b) provides exploded views of components of a base for receiving the curing light handle; and
• FIGS.10(a)-10(g) provides orthographic and perspective views of the base;
• In the various figures, like reference numerals wherever possible designate like or similar elements of the invention.
DETAILED DESCRIPTION
• FIGS.1(a)-1(f) present several views illustrating ahandle100 of an exemplary LED curing light embodying the principles of the present invention.FIG. 1(a) presents a perspective view of thehandle100. FIGS.1(b) and1(d) respectively present top and bottom elevation views of thehandle100. FIGS.1(c) and1(f) respectively present right side and left side views of thehandle100, andFIG. 1(e) presents a front view of thehandle100.
• Thehandle100 includes a grippingportion10 for an operator to hold thehandle100. The grippingportion10 encloses, for example, electrical circuit and battery components of the handle100 (not shown), and provides access to aswitch button cover11 for operating the curing light. Thehandle100 also houses at least one visual indicator12 (for example, comprising an LED) for indicating a current state or status of the curing light.
• Extending from the gripping portion of thehandle100 is aprobe portion13 of thehandle100 that has a diameter reduced from a diameter of the grippingportion10, and includes anangled bend14 near adistal end15 of theprobe portion14 in order that thedistal end15 may be conveniently positioned, for example, within a dental patient's mouth. This configuration enables alens assembly16 at thedistal end15 of the probe to be placed in close proximity to a patient's tooth, so that light emitted at thedistal end15 of theprobe portion13 may be used to cure a dental material that has been applied to the tooth.
• FIG. 2 provides an exploded view of the curinglight handle100, includingright housing case101, aleft housing case102, an LED/heat sink subassembly20, and anoptical choke16aand aball lens16bpositioned in proximity to anLED21. Theball lens16bis configured to be removable and replaceable.Optical choke16aand aball lens16bare selected so that theLED21 produces a focused light output at thedistal end15 of theprobe portion13.FIG. 2 also illustrates a curing lightcircuit board assembly30, electrically coupled to each of theLED21, abattery41, and abattery charging terminal42 of thehandle100. Aswitch button cover11 made of neoprene or some like material covers anoperating switch31 mounted on thecircuit board30, and protrudes through thecases101,102 to provide external means for operating the curing light. An indicator cover12aand alight pipe12bare positioned over an indicator LED on thecircuit board assembly30. Indicator cover12aprotrudes from thecircuit board assembly30 through thecases101,102. Audio circuitry (not shown) for producing an audible indicator (for example, a “beep”) is also positioned oncircuit board assembly30.
• FIGS.3(a)-3(d) present several views illustrating aheat sink22 of the LED/heat sink subassembly20, for dissipating heat primarily generated by theLED21 ofFIG. 2.FIG. 3(a) presents a perspective view of theheat sink22. FIGS.3(b) and3(d) respectively present top and bottom elevation views of theheat sink22, andFIG. 3(c) presents a side view of theheat sink22.
• Theheat sink22 conforms to an inner volume of theprobe portion13 ofFIG. 1, and substantially fills this inner volume. Preferably formed in a single piece, it extends through theangled bend14 of theprobe portion13 ofFIG. 1 in order to be directly and thermally coupled to theLED21 ofFIG. 2. Theheat sink22 includes, for example,lateral grooves23 on opposing sides ofheat sink22 for directing electrical wires from theLED21 ofFIG. 2 to thecircuit board assembly30 ofFIG. 2.Heat sink22 is also includesnotches24 on opposing sides ofheat sink22 at adistal end25 of the heat sink in order to locatably couple theLED21 at thedistal end25 Theheat sink22 preferably comprises a highly thermally conductive material such ascopper101.
• FIGS.4(a)-4(d) provide several views of aball lens16baffixed to the curing light handle for focusing light emitted by the LED.FIG. 4(a) presents a perspective view of theball lens16b. FIGS.4(b) and1(c) respectively present top and bottom elevation views of theball lens16b, andFIG. 4(c) presents a section view through section A-A ofFIG. 4(c).
• Theball lens16b, in conjunction with theoptical choke16aillustrated inFIG. 2, further focuses a light beam emitted by theLED21 ofFIG. 2.Ball lens16bandoptical choke16aare selected so that a majority of the emitted light energy is concentrated over an area that is sufficient for curing dental composites in a patient's mouth.
• FIGS.5(a)-5(d) and6(a),6(b) respectively illustrate features ofleft housing case102 and aright housing case101, respectively. Theright housing case101 and lefthousing case102 may be mated for example by ultrasonic welding. An energy director102aof theleft housing case102 includes an outwardly extending v-shaped edge102b(see, e.g., Section F-F ofFIG. 5(a),5(b)) that may be positively located and mated to a corresponding groove (not shown) in the right housing case (see, e.g., Section B-B ofFIG. 6). In addition, the v-shaped edge of the energy director is periodically relieved by an inwardly extending v-shapedgroove102c(see, e.g., Detail G ofFIG. 5(c)) that in order to receive aweld lock101bof the left housing case (see, e.g., Detail H ofFIG. 6(b)). In this manner, the left housing case and right housing case can be easily, precisely and fixedly aligned for mating during the ultrasonic welding process. Once ultrasonically welded, the left housing case and right housing case form a rigid, one-piece housing for the handle.
• FIG. 7 presents a schematic diagram of acircuit700 for operating the curing light handle. Thecircuit700 is preferably powered by a conventional lithium battery (illustrated asbattery41 ofFIG. 2), but may alternatively be powered by a conventional nickel cadmium battery, or alternatively, by a nickel metal hydride battery.
• Switch701signals switching controller702 viamicrocontroller703 to turn onLED21 for a predetermined curing cycle (for example, sixty seconds).Microcontroller703 is coupled tocrystal oscillator704 to provide timed control functions. After completion of the curing cycle,microcontroller703 removes power fromLED21 to allow the curing light to enter a sleep mode.
• During operation ofLED21,microcontroller703 periodically outputs a signal onpin1 of microcontroller703 (for example, every ten seconds) to causespeaker705 to produce a regularly timed audible beep. These beeps may be used by a dentist or other operator of thehandle100 ofFIG. 1 to determine an elapsed time, and thereby to apply the curing light to cure a dental material for a desired curing time. A chargingcircuit706 and fuse707 regulate battery charging and prevent the battery from being overcharged.
• Microcontroller703 is further programmed to periodically test for adequate battery voltage and excessive operating temperature (for example, every five seconds). For example,microcontroller703 determines the adequacy of battery voltage Vdd by measuring and comparing Vdd as supplied to thecircuit700 to a fixed voltage reference measured acrossdiodes708,709.Microcontroller703 further determines operating temperature by measuring a voltage drop across a resistive component ofthermistor710 relative to Vdd. As the voltage drop across the thermistor is a function of Vdd, a dimensionless ratio of these two voltages may be produced to determine a relative measure of operating temperature.
• If either battery voltage is determined to be inadequate and/or operating temperature is determined to be excessive,microcontroller703 does not permit a new operating cycle to begin in response to an operation ofswitch701. If an operating cycle is in progress when battery voltage is determined to be inadequate and/or operating temperature is determined to be excessive,microcontroller703 allows the currently operating cycle to complete before preventing initiation of subsequent operating cycles. While battery voltage and operating temperature are at proper levels for operation,microcontroller703 controls a voltage atpin6 to light indicatingLED711.
• In order to provide for change and upgrading of its operating program,microcontroller703 may further be coupled toprogramming connector712.
• FIG. 8 presents a schematic diagram of acharging circuit800 for chargingbattery41 ofFIG. 2 by means ofbase200 ofFIGS. 9, 10. As illustrated inFIG. 8,linear regulator801 regulates a voltage supplied to the charging circuit800 (for example, from a commercial power source). So long as adequate commercial power is supplied,green LED802 lights to provide an indication that commercial power is present. As significant current is drawn at lead J2 for recharging the battery, a voltage drop acrossresistors803,804 activatesamplifiers805,806 to cause current flow throughtransistor807 in order to light thered LED808 to indicate that the battery is recharging.
• FIGS.9(a),9(b) respectively provide exploded views of components of abase200 for receiving the curing light handle from above and below thebase200. The components ofbase200 include amain housing201, alower housing202, acircuit board203 including a batterycharger pin assembly203aand apower receptacle203b, and aweight204 for stabilizing the circuit board.FIG. 10 provides orthographic and perspective views of the base. The components201-204 may be assembled together using a variety of conventional fastening means (for example, by means of retainingpins205 which may be ultrasonically welded, glued or thread mounted toreceptacles206.
• FIGS.10(a)-10(g) further illustrate thebase200.FIG. 10(a) presents a perspective view of thebase200. FIGS.10(b) and10(c) respectively present top and bottom elevation views of thebase200. FIGS.10(e) and10(g) respectively present right side and left side views of thebase200.FIG. 10(f) presents a front view of thebase200, andFIG. 10(g) provides a rear view of thebase200.
• Main housing201 includes aconical portion201ahaving arecess201bfor receiving the gripping portion of the handle for storage and re-charging of the handle. Theconical portion201aandrecess201bare co-axially oriented slightly away from avertical angle201c(for example, approximately 10 to 15 degrees). Aslit201dextends through the conical201aportion into therecess201b, and terminates at alowest portion201eof a base of theconical portion201ain order to enable moisture collecting within the interior of therecess201bto drain away through the slit. At least two charging pins in chargingpin assembly203aofFIG. 9 extend upward from the recess near the base of theconical portion201afor contact withbattery charging terminal42 ofFIG. 2 at the ofhandle100. The chargingterminal42 includes at least two, electrically isolated conductive rings (not shown). When the handle is inserted into the recess, each pin makes electrical contact with one of the conductive rings, regardless of the radial orientation of the handle in the recess.
• Appendix 1 provides a program listing illustrating for example the manner in which microcontroller U2 ofFIG. 7 is operated to measure battery voltage and thermistor temperature, and therefrom to control operation of the curing cycle and lighting of the visual status indicator.
• The foregoing describes the invention in terms of embodiments foreseen by the inventor for which an enabling description was available, notwithstanding that insubstantial modifications of the invention, not presently foreseen, may nonetheless represent equivalents thereto.

  APPENDIX 1
  ;**********************************************************************
  ;  Program for the LED curing light                    *
  ;  Microcontroller used is the 8 pin PIC12F675.               *
  ;                                 *
  ;**********************************************************************
  ;                                 *

  ;   Filename:	LEDcure_Vx.asm
  *

  ;   Date:	February 20, 2003               *
  ;   File Version:	03032716  (YYMMDDHH)          *

  ;                                 *

  ;   Author:	Douglas J. Mansor               *
  ;   Company:	Coltene/Whaledent, Inc.             *

  ;                                 *

  ;                                 *

  ;**********************************************************************

  ;                                 *

  ;   Files required:

  p12f675.inc               *

  ;                                 *

  ;                                 *

  ;                                 *

  ;**********************************************************************

  ;                                 *

  ;   Notes:                            *

  ;                                 *

  ;                                 *

  ;                                 *

  ;                                 *

  ;**********************************************************************

  ;

  list	p=12f675	; list directive to define processor
  #include	<p12f675.inc>	; processor specific variable
  definitions
  ;

  errorlevel  −302	; suppress message 302 from list
  file
  ;

  ——CONFIG  _CP_ON & _WDT_OFF & _MCLRE_OFF & _PWRTE_OFF & _LP_OSC &

  _BODEN_OFF

  ; ‘——CONFIG’ directive is used to embed configuration word within .asm

  file.

  ; The lables following the directive are located in the respective .inc

  file.

  ; See data sheet for additional information on configuration word

  settings.

  ;

  ;

  ;***** VARIABLE DEFINITIONS

  w_temp	EQU	0x50	; variable used for context
  saving

  status_temp	EQU	0x51	; variable used for context saving
  ;
  STATE	EQU	0x20	;STATE machine indicator

  OVERTEMP	EQU	H‘0000’	;Hot bit in STATE
  UNDERVOLTAGE	EQU	H‘0001’	;Low voltage bit in STATE

  LIGHTON	EQU	H‘0002’	;Light on bit in STATE
  ;

  TIME	EQU	0x21	;Timer overflow count, 10s count
  THERH	EQU	0x22	;High temperature byte
  THERL	EQU	0x23	;Low temperature byte
  VOFFH	EQU	0x24	;Battery voltage with light off,
  high byte
  VOFFL	EQU	0x25	;Battery voltage with light off, low
  byte
  VONH	EQU	0x26	;Battery voltage with light on, high
  byte
  VONL	EQU	0x27	;Battery voltage with light on, low
  byte

  ACCUMH	EQU	0x30	;Accumulator, high byte
  ACCUML	EQU	0x31	;Accumulator, low byte
  ACCUMB	EQU	0x32	;Accumulator B. Counts cycles
  of beep.

  TEMP1	EQU	0x33	;Temporary register storage 1
  TEMP2	EQU	0x34	;Temporary register storage 2
  LOOPCTR1	EQU	0x35	;For counting Mainloops
  LOOPCTR2	EQU	0x36	;For counting loops
  VMINL	EQU	0x80	;coresponds to 3.5V with 1.44V Ref.
  LOOPS	EQU	0x20	;delay 32 × 256 loops

  TENS	EQU	0x6	;Light ON time in 10s
  intervals

  SEC5	EQU	0x5F	;for 5s timing. 32768kHz osc =
  122.07us cyc

  ;	256 * 160 * 122.07031us
  = 5s, 160d = A0h
  ;	FFh − A0h = 5Fh

  TMR1SETH	EQU	0D7h	;The high byte of timer1 preset for
  10s
  TMR1SETL	EQU	0FFh	;The low byte of timer1 preset for
  10s

  ;  for prescaler = 1:8 and Fosc = 32768 Hz

  ;

  ;

  ;**********************************************************************

  	ORG	0x000	; processor reset vector
  	goto	main	; go to beginning of program
  ;
  ;
  	ORG	0x004	; interrupt vector location
  	movwf	w_temp	; save off current W register

  contents

  movf

  STATUS,w

  ; move status register into W

  register

  movwf

  status_temp

  ; save off contents of STATUS

  register

  ;

  ;

  ; INTERRUPT code can go here or be located as a call subroutine

  elsewhere

  ;———————————————

  	clrf	PIR1	;Clear IRQ flags
  	movlw	0C0h	;Enable peripheral IRQs
  	movwf	INTCON	;& disableTimer 0 IRQ and

  external IRQ

  ;  Verify STATE

  btfsc

  STATE,LIGHTON

  ;Is the Light on?

  goto

  IRQ_ok

  ;The light is on and being

  timed

  call

  stopall

  ;The Timer isn't supposed to

  be running!

  goto

  IRQ_return

  ;stop it and exit IRQ

  IRQ_ok:

  	movlw	TMR1SETH	;load with 10240 counts at 976.562us
  	movwf	TMR1H	;before next IRQ
  	movlw	TMR1SETL
  	movwf	TMR1L

  decfsz

  TIME,1

  ;bump 60s time keeper

  goto

  not60yet

  ;  Maximum on time has been reached.

  call

  stopall

  ;subroutine to turn off big

  LED and stop timer

  not60yet:

  call

  beepone

  ;execute a beep

  bcf

  PIR1,TMR1IF

  ;Clear the Timer 1 IRQ flag

  ;

  IRQ_return:

  ;———————————————

  	movf	status_temp,w	; retrieve copy of STATUS register
  	movwf	STATUS	; restore pre-isr STATUS register

  contents

  	swapf	w_temp,f
  	swapf	w_temp,w	; restore pre-isr W register

  contents

  retfie

  ; return from interrupt

  ;

  main:

  ;

  ;----------INITIALIZE-------------

  ; setup GPIO, 2,3 (pins 5,4) as input,

  ; 0,1,4,5 (pins 7,6,3,2) as output,

  ; analog mode off

  bcf

  STATUS, RP0

  ;Bank 0

  clrf

  GPIO

  ;Init GPIO

  movlw

  07h

  ;Set GP<2:0> to

  movwf

  CMCON

  ;digital I0 (Turn off the

  comparator)

  bsf

  STATUS, RP0

  ;Bank 1

  movlw

  039h

  ;Set GP<5:4:3:0> as inputs (0=out,

  1=in)

  	movwf	TRISIO	;and set GP<2:1> as outputs
  	movlw	00h	;Don't turn on any weak

  pullups

  movwf

  WPU

  ;GP3 doesn't have a pullup

  clrwdt

  ;Clear the doggie

  movlw

  87h

  ;Disable weak pullups and GP2

  not clk source

  movwf

  OPTION_REG

  ;setup OPTION register. Enable

  Timer0 & /256

  clrf

  IOCB

  ;Disable Interrupts for input

  changes

  movlw

  01h

  ;Enable A/D 0 (pin7) & A/D

  clock = Fosc/2

  	movwf	ANSEL	;Disable the other A/D inputs
  	movlw	01h
  	movwf	PIE1	;Enabletimer 1 overflow interrupt

  bcf

  STATUS, RP0

  ;Bank 0

  bsf

  GPIO,2

  ;turn on the weak pullup

  for GP2

  movlw

  81h

  ;Right justify output, Vdd =

  REF

  movwf

  ADCON0

  ;select AD0, Turn on A/D power

  movlw

  0C0h

  ;Enable peripheral IRQs

  movwf

  INTCON

  ;& disableTimer 0 IRQ and

  external IRQ
  ;	and port change
  IRQ

  	clrf	PIR1	;Clear IRQ flags
  	clrf	TMR1L
  	clrf	TMR1H

  movlw

  31h

  ;1:8 prescale,timer 1 ON

  	movwf	T1CON	;andtimer 1 gate enabled
  	clrf	STATE
  	clrf	TIME

  ;

  ;

  beginhere:

  ; This is where the program will actually start.

  ; Some setup items will occur before getting into the main loop

  ;

  ; Clear first half of RAM (Should disable IRQ first?-----------)

  	movlw	20h	;initialize pointer
  	movwf	FSR	;to point at RAM

  NEXT: clrf

  INDF

  ;clear the INDF register

  	incf	FSR,1	;increment the pointer
  	btfss	FSR,6	;maybe done?
  	goto	NEXT	;no, keep at it

  	bsf	GPIO,1	;Green off
  	bsf	GPIO,2	;big LED off

  ;	movlw	LOOPS	;reset the loop counter
  ;	movwf	LOOPCTR2	;to “LOOPS” value

  ;Setup Timer 0 for Temperature and voltage checking

  	movlw	SEC5	;get the preset value
  	movwf	TMR0	;intotimer 0

  ;

  Mainloop:

  btfss

  GPIO,3

  ;test GP3 for a low condition

  (pin 4)

  goto

  buttondown

  ;perform button down sequence

  ;	incfsz	LOOPCTR1,1	;don't check temp & Vcc very
  often

  ;

  goto

  Mainloop

  ;delay 256 loops (might need more)

  ;	decfsz	LOOPCTR2,1	;delay up to 65768 loops
  ;	goto	Mainloop	;more loops
  ;	movlw	LOOPS	;reset the loop counter
  ;	movwf	LOOPCTR2	;to “LOOPS” value

  ; Check the 5 second timer for Temperature and voltage checking

  	movf	TMR0,0	;Get thecurrent timer 0value
  	addlw
  	1	;bump the count to get off

  dead center

  sublw

  SEC5

  ;SEC5-TMR0. sets carry unless

  overflow

  btfss

  STATUS,C

  ;skip next if no carry (carry; C =

  0)

  	goto	Mainloop	;go loopy
  	movlw	SEC5	;get the preset value
  	movwf	TMR0	;intotimer 0

  ;

  clrwdt

  ;Clear the prescaler

  ; Test T & V

  	btfsc	STATE,LIGHTON	;check if light is on
  	goto	lightison
  	call	convert1_off	;since light is off, read off

  battery voltage

  ;  Test that battery voltage is high enough

  btfsc

  VOFFH,1

  ;Test bit 1 of off voltage.

  high = battery too low

  goto

  low_battery

  ;flag the low battery signal

  btfss

  VOFFH,0

  ;check the 0 bit of off

  voltage. 0 = high volts

  goto

  high_batt

  ;ifbit 0 = 1, must test the low

  byte

  movlw

  VMINL

  ;get the minimum Vcc limit

  subwf

  VOFFL,0

  ;compare with the minimum

  acceptable voltage

  	btfsc	STATUS,C	;if C = 0 then voltage is OK
  	goto	low_battery

  high_batt:

  ;clear the low battery flag and light green light

  bcf

  STATE,UNDERVOLTAGE

  ;voltage OK

  goto

  Mainloopskp1

  low_battery:

  bsf

  STATE,UNDERVOLTAGE

  ;voltage too low

  goto

  Mainloopskp1

  lightison:

  call

  convert1_on

  ;read light-on battery voltage

  ;  Test that battery voltage is high enough

  btfsc

  VONH,1

  ;Test bit 1 of on voltage.

  high = battery too low

  goto

  low_battery

  ;flag the low battery signal

  btfss

  VONH,0

  ;check the 0 bit of on

  voltage. 0 = high volts

  goto

  high_batt

  ;ifbit 0 = 1, must test the low

  byte

  movlw

  VMINL

  ;Get the minimum Vcc limit

  subwf

  VONL,0

  ;compare with the minimum

  acceptable voltage

  	btfsc	STATUS,C	;if C = 0 then voltage is OK
  	goto	low_battery	;If low
  	goto	high_batt	;If high

  Mainloopskp1:

  ;  Check diode temperature

  	call	convert0	;read temperature
  	call	Checkstate
  	goto	Mainloop

  buttondown:

  btfsc

  GPIO,3

  ;is the button still down?

  goto

  Mainloop

  ;if not down

  btfsc

  GPIO,3

  ;check button a third time

  goto

  Mainloop

  ;if not still down

  ;  Only turn on the big LED if STATE = 0

  	clrw
  	iorwf	STATE,0	;check if STATE = 0

  btfsc

  STATUS,Z

  ;zero flag is 0 if STATE /= 0

  goto

  turnon

  ;go turn on the big LED

  	btfss	STATE,LIGHTON	;is the big LED on?
  	goto	release_wait	;if not, can't turn it on

  ;  Turn off the big LED

  call

  stopall

  ;lights off,timer stop, flags

  clear

  goto

  release_wait

  turnon:

  bcf

  GPIO,2

  ;turn on the big LED

  bsf

  STATE,LIGHTON

  ;set the LED ON flag

  ;  Start TIMER 1

  	movlw	TMR1SETH	;load with 10240 counts at 976.562us
  	movwf	TMR1H	;before next IRQ
  	movlw	TMR1SETL
  	movwf	TMR1L
  	movlw	TENS	;prep TIME for count of 10s periods
  	movwf	TIME	;set the time counter

  bcf

  PIR1,TMR1IF

  ;clear any pending IRQ flag

  from timer 1

  	bsf	STATUS, RP0	;Bank 1
  	bsf	PIE1, TMR1IE	;be sure timer 1 IRQ is

  enabled

  	bsf	INTCON,GIE	;global IRQ enabled
  	bsf	INTCON,PEIE	;peripherial IRQ enabled
  	bcf	STATUS, RP0	;Bank 0
  	bsf	T1CON,TMR1ON	;enable timer

  ;	movlw	LOOPS	;reset the loop counter
  ;	movwf	LOOPCTR2	;to “LOOPS” value
  ;	clrf	LOOPCTR1	;To count idle loops & sync w/beeps

  ; Synchronize the 5 second timer

  	movlw	SEC5	;get the preset value
  	movwf	TMR0	;into timer 0

  clrwdt

  ;Clear the prescaler

  call

  beepone

  ;execute a beep

  ;

  release_wait:

  btfss

  GPIO,3

  ;test GP3 for high

  goto

  release_wait

  ;loop if still low

  btfss

  GPIO,3

  ;test GP3 for high

  goto

  release_wait

  ;loop if still low

  btfss

  GPIO,3

  ;test GP3 for high

  	goto	release_wait	;loop if still low
  	goto	Mainloop	;go back to main looping when

  released

  ;

  loophere:

  goto

  loophere

  ;Tightloop, wait for reset or IRQ

  ;

  ;

  ; --------SUBROUTINES------------

  beepone:

  clrf

  ACCUMB

  ;Clear the LS count location

  beeploop:

  bsf

  GPIO,1

  ;1 start by pulling the

  line high

  bcf

  GPIO,1

  ;1 clear the output

  decfsz

  ACCUMB,1

  ;1 bump the counter and test,

  skip if zero

  	goto	beeploop	;2 keep at it
  ;	call	convert1_on	;read Vcc with light on

  bsf

  GPIO,1

  ;Green off

  call

  Checkstate

  ;control the green LED state

  ; reset the 5 second timer before it goes off

  	movlw	SEC5	;get the preset value
  	movwf	TMR0	;into timer 0

  ;	clrwdt	;Clear the prescaler
  ;

  ;	movlw	LOOPS	;reset the loop counter
  ;	movwf	LOOPCTR2	;to “LOOPS” value
  ;	clrf	LOOPCTR1	;To count idle loops & sync w/beeps

  return

  ; when done 255 cycles

  * 7 inst cycles = .218s

  ;

  convert0:

  ;   A/D conversion on input AD0 to measure temperature of thermistor

  ;   Result is left in ADRESH and ADRESL

  bcf

  GPIO,1

  ;pull the other side of

  the reference low
  ;	lights the green LED
  also

  bsf

  ADCON0,1

  ;Start the conversion

  convert0_wait:

  	btfsc	ADCON0,1	;check for done
  	goto	convert0_wait	;keep checking til done
  	call	Checkstate	;control the green LED state
  	movf	ADRESH,0	;Save temperature in THERH, THERL
  	movwf	THERH

  bsf

  STATUS, RP0

  ;Bank 1

  	movf	ADRESL,0
  	movwf	THERL

  bcf

  STATUS, RP0

  ;Bank 0

  btfss

  THERH,0

  ;check for overtemp (>90C)

  bsf

  STATE,0

  ;set over temperature

  flag if maybe high

  btfsc

  THERH,1

  ;check high order bit

  bcf

  STATE,0

  ;clear over temperature

  flag if sure heat is OK

  return

  ;when done

  ;

  ;

  ;

  convert1_off:

  ;   A/D conversion on input AD1 to measure battery voltage

  ;  with the light off.

  ;   Result is left in VOFFH and VOFFL

  	bsf	STATUS, RP0	;Bank 1
  	bsf	TRISIO,1	;Change GP/AD1 from output to

  input (pin 6)

  	bsf	ANSEL,ANS1	;make AD1 active
  	bcf	TRISIO,0	;change GP0 (pin 7) from input

  to output

  bcf

  STATUS, RP0

  ;Bank 0

  bcf

  GPIO,0

  ;pullpin 7 low (GP0)

  bsf

  ADCON0,CHS0

  ;select pin 6, AD1 for

  conversion

  bsf

  ADCON0,GO

  ;Start the conversion

  convert1_off_wait:

  btfsc

  ADCON0,NOT_DONE

  ;check for done

  	goto	convert1_off_wait	;keep checking til done
  	movf	ADRESH,0	;Save temperature in THERH, THERL
  	movwf	VOFFH	;get the high bits

  bsf

  STATUS, RP0

  ;Bank 1

  movf

  ADRESL,0

  ;A/D low byte and TRISIO are inbank

  1

  movwf

  VOFFL

  ;get the low byte

  	bcf	TRISIO,1	;change pin 6 back to output
  	bsf	TRISIO,0	;change GP0 (pin 7) back to

  input

  	bcf	ANSEL,ANS1	;inactivate AD1
  	bcf	STATUS, RP0	;Bank 0
  	bcf	ADCON0,CHS0	;reselect AD0

  return

  ;when done

  ;

  convert1_on:

  ;   A/D conversion on input AD1 to measure battery voltage

  ;  with the light on.

  ;   Result is left in VONH and VONL

  	bsf	STATUS, RP0	;Bank 1
  	bsf	TRISIO,1	;Change GP/AD1 from output to

  input(pin 6)

  bcf

  TRISIO,0

  ;change GP0 (pin 7) from input

  to output

  	bsf	ANSEL,ANS1	;make AD1 active
  	bcf	STATUS, RP0	;Bank 0

  bcf

  GPIO,0

  ;pullpin 7 low (GP0)

  bsf

  ADCON0,CHS0

  ;select pin 6, AD1 for

  conversion

  bsf

  ADCON0,GO

  ;Start the conversion

  convert1_on_wait:

  	btfsc	ADCON0,NOT_DONE	;check for done
  	goto	convert1_on_wait	;keep checking til done
  	movf	ADRESH,0	;Save temperature in VONH, VONL
  	movwf	VONH

  bsf

  STATUS, RP0

  ;Bank 1

  	movf	ADRESL,0
  	movwf	VONL

  	bcf	TRISIO,1	;change pin 6 back to output
  	bsf	TRISIO,0	;change GP0 (pin 7) back to

  input

  	bcf	ANSEL,ANS1	;inactivate AD1
  	bcf	STATUS, RP0	;Bank 0
  	bcf	ADCON0,CHS0	;reselect AD0

  return

  ;when done

  ;

  ;

  Checkstate:

  bcf

  TEMP1,1

  ;default to green-on.

  btfsc

  STATE,OVERTEMP

  ;is diode too hot?

  bsf

  TEMP1,1

  ;green-off if hot.

  btfsc

  STATE,UNDERVOLTAGE

  ;is battery too low?

  bsf

  TEMP1,1

  ;green-off if battery is

  low.

  	btfsc	TEMP1,1
  	goto	CKstate_set

  bcf

  GPIO,1

  ;Green on

  goto

  CKstate_done

  CKstate_set:

  bsf

  GPIO,1

  ;Green Off

  CKstate_done:

  return

  ;

  ;

  stopall:

  ;   Turn off the big LED

  bsf

  GPIO,2

  ;turn big LED off

  ;   StopTimer 1

  	bcf	T1CON,TMR1ON	;stoptimer 1
  	bcf	PIR1,TMR1IF	;clear the IRQ flag

  ;

  bcf

  STATE,LIGHTON

  ;clear the LED ON flag

  call

  Checkstate

  ;set/reset the green LED

  call

  beepone

  ;execute a beep

  return

  ;

  ;

  END

  ;directive ‘end of

  program’

Claims (16)

1. A portable curing light for dental applications, comprising:

a grippable handle;

a lens assembly mounted at a distal end of a probe portion of the grippable handle;

a light source positioned in proximity to the lens assembly, said light source including only one light emitting diode (LED);

a switch, said switch being operable at the grippable handle;

an operating circuit mounted within the grippable handle, said operating circuit being responsive to said switch for initiating a curing cycle of the portable curing light; and

a battery mounted within the grippable handle for providing power to the operating circuit for powering the light source during the curing cycle;

wherein the probe portion of the grippable handle has a first length and a first diameter that is reduced from a second diameter of a grippable portion of the grippable handle, and bends at a predetermined angle near the distal end, wherein the first length, first diameter and predetermined angle are selected for positioning the distal end in proximity to a dental material to be cured in a patient's mouth.

2. The portable curing light ofclaim 1, further comprising:

a heat sink directly for dissipating heat, said heat sink directly mounting the LED and substantially filling an inner cavity of the probe portion and including a bent portion bent at the predetermined angle.

3. The portable curing light ofclaim 1, wherein the lens assembly includes a ball lens.

4. The portable curing light ofclaim 1, wherein a lens of the lens assembly is removable.

5. The portable curing light ofclaim 3, wherein the lens assembly further includes an optical choke positioned between the ball lens and the LED.

6. The portable curing light ofclaim 1, wherein the ball lens is replaceably mounted at the distal end of the probe portion.

7. The portable curing light ofclaim 1, further comprising:

a base unit for receiving the portable curing light, the base unit including:

a main housing having a conical portion with a recess for receiving the grippable handle and a vertical slit that opens said recess to an exterior of the conical portion, said recess having a base portion that is positioned at a second predetermined angle from the horizontal plane and a longitudinal axis that is perpendicular to the base portion, and said vertical slit being positioned to terminate at a lowest point of said base portion.

8. The portable curing light ofclaim 7, wherein said base unit further includes:

a pin assembly for electrically contacting a battery charging terminal at a base of the grippable handle, and

a power receptacle for conducting power from an external power source to the pin assembly.

9. The portable curing light ofclaim 2, wherein said heat sink comprises a metallic conductor formed in a single piece.

10. The portable curing light ofclaim 9, wherein said heat sink further comprises one or more lateral grooves on one or more sides of said heat sink for directing electrical wires between said LED and said operating circuit.

11. The portable curing light ofclaim 1, wherein said operating circuit operates to activate at least one visual indicator, said at least one visual indicator indicating at least one of an adequate power level for said battery and a condition of charging said battery.

12. A method for ultrasonically welding a mating pair of plastic housings, the method comprising the steps of:

providing a mating edge of a first housing in the pair of plastic housings with an ultrasonic energy director, said ultrasonic energy director having an outwardly extending v-shaped edge along said mating edge of said first plastic housing;

providing a mating edge of a second housing in the pair of plastic housings with an inwardly-extending v-shaped groove along said mating edge of said second housing;

periodically relieving said v-shaped edge along said mating edge of said first plastic housing with a v-shaped groove positioned across said mating edge of said first plastic housing;

periodically adding an outwardly extending v-shaped edge across said inwardly-extending v-shaped groove along said mating edge of said second housing; and

mating said first and said second housings, such that said outwardly extending v-shaped edge along said mating edge of said first plastic housing mates with said inwardly-extending v-shaped groove along said mating edge of said second housing, and one or more of said periodic v-shaped grooves across said mating edge of said first plastic housing mate with one or more of said periodic v-shaped edges across said mating edge of said second plastic housing.

13. The method ofclaim 12, further comprising the step of:

ultrasonically welding said mating edge of said first plastic housing to said mating edge of said second plastic housing.

14. A method for controlling the operation of a dental curing light, the method comprising the steps of:

monitoring a battery voltage of the dental curing light;

monitoring an operating temperature of the dental curing light;

comparing a value of the monitored battery voltage to a first threshold value;

comparing a value the monitored operating temperature to a second threshold value;

determining whether the dental curing light is currently operating in an a curing cycle; and

while the dental curing light is not operating in a current curing cycle, preventing initiation of a next curing cycle if at least one of the monitored battery voltage and operating temperature values exceeds its associated threshold value.

15. The method ofclaim 14, further comprising the step of:

producing one or more audible signals at periodic intervals while the dental curing light is operating in the current curing cycle.

16. A base unit for storing a portable curing light, the base unit including:

a main housing having a conical portion with a recess for receiving the portable curing light and a vertical slit that opens said recess to an exterior of the conical portion, said recess having a base portion that is positioned at a predetermined angle from the horizontal plane and a longitudinal axis that is perpendicular to the base portion, and said vertical slit being positioned to terminate at a lowest point of said base portion.

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